The difference and sum of projectors
JJ Koliha, V Rakocevic, I Straskraba
LINEAR ALGEBRA AND ITS APPLICATIONS | ELSEVIER SCIENCE INC | Published : 2004
The aim of this paper is to present new results on the invertibility of the sum of projectors, and new relations between the nonsingularity of the difference and the sum of projectors. We also give simple proofs, without referring to rank theory, of some results on the nonsingularity of the difference of projectors obtained by Groß and Trenkler [SIAM J. Matrix Anal. Appl. 21 (1999) 390]. © 2004 Elsevier Inc. All rights reserved.